# Inventory Reorder Point Calculator

> Reorder point calculator: combine lead time demand and safety stock to find exactly when to reorder inventory. Editable inputs, free, runs in your browser.

- **Canonical URL:** https://boringtoolskit.com/inventory-reorder-point-calculator/
- **Category:** Seller & Business
- **Evidence level:** authored-methodology
- **Reviewed:** July 2026
- **Last verified:** 2026-09-20
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Lead-time demand = average daily sales × supplier lead-time days. Reorder point = lead-time demand + entered safety stock. The order-now signal activates when current stock is at or below that point.

## Worked example

10 units per day, seven lead-time days, and 20 safety-stock units produce a 90-unit reorder point. At 80 units on hand, the trigger is active.

## Assumptions

- Average daily demand and supplier lead time remain constant.
- Safety stock is entered explicitly rather than inferred from a service level.
- Open purchase orders, seasonality, minimum order quantities, spoilage, backorders, and multi-location inventory are excluded.

## Common questions

### What is the reorder point formula?

Reorder point equals average daily sales multiplied by lead time days, plus safety stock units.

### When should I reorder inventory?

Reorder when current stock is at or below the calculated reorder point.

### What is lead time demand?

Lead time demand is the inventory expected to sell during replenishment lead time: average daily sales times lead time days.

## Related tools

- /cash-flow-runway-calculator/
- /break-even-units-calculator/
- /amazon-seller-fee-calculator/

## Sources

- [Manage your finances](https://www.sba.gov/business-guide/manage-your-business/manage-your-finances)

---

*Local planning estimate. Verify current terms, rates, and policies before acting.*